Unit 4 is very strange and is a sort of hodge podge of information. When I've done this unit in the past the students have struggled greatly with the concepts in the last two worksheets. The Combining Volumes of Gases and then the Mass ratio stuff. We did find on the last worksheet if we took off the wrong scenario...students were able to pick it up better. I get why they have that there, but it just makes it more confusing.

We're actually switching unit 5 and 6 this year to see if going bonding, formula writing...then moles, reactions stoich is beter than moles, formulas/bonding, reactions, stoich.

As a forewarning..the modeling curriculum seems to make naming compunds/writing formulas seem like a 1 or 2 day task...but its more like 1 or 2 weeks.

I was kind of forced into the modeling curriculum and there are some things I like and many things I don't. I supplement the curriculum quite a bit with other labs and activities to help reinforce the ideas.

Chris Leverington

3950 Activity Points

Thank you for all of your input.

As things have gone so far, my cooperating teacher has drawn off of work of teachers in the community, and now has a few other activities and worksheets incorportated to better integrate and promote student learning. In regards to worksheet 3 - which is worksheet 5 in the sequence which I am drawing from my cooperating teacher - I have found a better manner to promote student understanding in the first section, where, according to AMTA's teacher's notes, we essentially have to "make the students believe" that different types of gases at the same pressure and temperature have the same number of particles.

To help the transition, I chose to draw off the model back in unit 2 where they do the pressure labs, and learning that pressure only generally changes under three tennants: changes in volume, changes in temperature, and changes in the number of gas particles. As an intermitent transition, I then asked them how they thought equal volumes of pure oxygen and one of pure hygrogen would compare in pressure. We went through if they were both at room temperature then their temperatures were the same, if they were both at 10 mL then their volumes were the same, and were left with the number of particles... not yet entirely touching yet if they were the same pressure or not.

To help them determine that, I then drew the connection towards the use of the Hoffman Apparatus. Pretending for a minute that it is a closed system if we were to close off the top of it, without confusing them with some of the details about hydrolic pressure, I asked them if "we can have two different pressures inside a closed container", asking first from the perspective of the syrringes in the pressure lab, and then connecting it to the Hoffman apparatus; they all agreed that inside a closed system that the pressures need to equalize, and you cannot have two separate pressures. Finally, we recapped that there was twice the volume of hydrogen produced in respect to the oxygen, since we had used it to prove the chemical formula for water, H20.

Accounting that there was twice as much hydrogen, and that "one volume of hydrogen" took up the same amount of oxygen, I essentially had them verify that each "volume" had the same number of particles through reverse induction; they were both at the same temperature, same volume, and - as we discussed - same pressure, so then they must have the same number of particles, thus proving Avogadro's Hypothesis.

Further on, to help them conceptualize that different sized gases at the same temperature and volume can have the same pressure. I drew analogies and comparisons off of how temperature is determined from the amount of Kinetic Energy, KE=mv^2, and that pressure is determined by how often and how forceably the air particles are hitting the container they're in. I made an analogy to how the smaller gas particles would have to be moving mush faster to have the same amount of pressure as the bigger particles moving slower.

To help them visualize it, I drew an analogy to trying to move a gigantic snow ball; the small particles as a bunch of little kids trying to move it; the larger ones some huge body builders; the pressure of contact being their impact/ push on the snow ball. If there was the same number of each, the body builders would not have to exert as much effort relative to their total strength as the little kids to move the snow ball a certain amount as the little kids. The same thing applies of course with the air particles, as the bigger ones move slower at a given pressure and volume.

I thank you for the other points of input, and will keep them in mind as I am student teaching. I have come to like the modeling curriculum, as it helps to promote students thinking on and discovering a concept and why it works vs us just telling them, and them memorizing it without understanding it. Although, I do agree that some areas are lacking, and further material is needed, whether from your own creation or what you discover elsewhere.

If you are able to allocate the resource from online, some of the material my cooperating teacher is using was made available by "Modeling Chemistry TN Modeling Curriculum Committee Pope John Paul II High School". There are additional resources which have been added to it.

Thank you for your advice.

Andrew Jewett

333 Activity Points

Hello. I am an upcoming teacher, student teaching chemistry in Ohio. For my teaching, I am drawing from the modeling curriculum made available by the American Modeling Teachers Association (AMTA). For my student teaching, I will be drawing heavily off of both the curriculum made availabe by the AMTA, as well as my cooperating teacher's experience using this method.

However, I am still looking for and open to any advice from those experienced it before I start student teaching full time in the spring. I will be doing around Units 4-8 of AMTA's Modeling Curriculum. Thank you for any input you are willing to give.

Andrew Jewett

333 Activity Points